My invention relates generally to swimming pool covers and more particularly to devices and method for draining pool covers of the flexible plastic, water-impervious type.
Heretofore, it has been common practice to place a water-impervious permanent cover over the top surface of a swimming pool during the off-season, winter months to prevent leaves and other wind-blown debris from entering the water stored in the pool during the dormant period. Water is generally left in swimming pools, both in above-ground and in-ground designs, during the winter period for structural reasons, or for water conservation purposes. In some pool designs it is necessary to keep water in the pool to prevent sidewall collapse due to high ground water loading on the exterior of the sidewalls. Suffice it to say that it is quite common to employ a vinyl or other flexible plastic water-impervious cover over the pool water during the dormant months in most pool designs for the purpose of keeping foreign objects and other debris from accumulating therein during this period. Naturally, clean-up and pool preparation in the spring is made much easier when such debris is not present to contaminate the stored pool water.
A major problem encountered in the use of known flexible plastic pool covers results from the excess water which has accumulated on the top surface of the cover during the covered period. In use, a pool cover overlaps the pool perimeter and is anchored or affixed around the perimeter in a known manner such that the cover is permitted to sag somewhat down into the pool to rest on the water surface in the center area of the pool. A small, controlled depth of water on the top surface of the pool cover is desirable to provide a natural weight or anchor on a central area thereof in order to prevent whipping and tearing of the cover by wind. Unfortunately, as rain water and/or melted snow water accumulates on the cover over the winter months, the volume of water stored on the cover will increase to considerable levels. It is not at all uncommon for the pool owner to encounter an extremely great weight of water on the cover when the pool is ready to be re-opened in the spring. In some cases, the cover may tear under this great weight during the winter months. Commonly mixed with the collected volume of water on the cover is an assortment of decayed leaves, twigs and other accumulated debris, even sometimes including drowned animals, which may have fallen into the trapped water during the winter months.
Quite obviously it is desirable to keep such accumulated debris from entering the relatively clean pool water stored beneath the cover, but this is generally not possible unless the large volume of water on top of the cover is first removed. If the excess accumulated water is not drained by pumping or bailing prior to removing the cover, it is not uncommon that the weight of the accumulated water may tear the cover. Also, it is not uncommon that accumulated debris will flow over the cover edges into the clean stored pool water to contaminate the stored pool water while the cover is being removed.
The above problems associated with excess water accumulating on the surface of a pool cover during the winter months and subsequent tearing of the cover are eliminated by my invention. My invention provides an effective, yet inexpensive and easily installed drain device to continuously drain water from the cover. My invention further provides a pool cover drain device which maintains a constant volume of water of predetermined depth on the cover while continuously draining excess water accumulating above the predetermined desired level. In this manner a volume of water, of a predetermined weight, is maintained on the cover to prevent wind whipping damage to the cover which might otherwise occur if the cover were completely unweighted or insufficiently weighted. Still further, my invention provides a pool cover drain device which includes a vertically adjustable drain head closure which permits a variable depth of water to be accumulated on the cover to accommodate pool covers of various surface areas, which require varying weights of water for surface hold-down purposes. Thus for large surface area pool covers, the drain closure head is adjusted upwardly to permit a greater depth of water to accumulate thereon for weighting purposes.
Further, my invention provides a drainage device for pool covers suitable for use on both above-ground and in-ground pools which drains accumulated water through an existing pool sidewall port of the pool.